1. Field of the Invention
The present invention relates to an air passage opening/closing device which opens and closes an air passage by using a film member (a film door). The air passage opening/closing device is suitably used for a vehicle air conditioner.
2. Related Art
An air passage opening/closing device, which opens and closes an air passage by using a film member, is proposed in JP-A-5-23824 and the like. In this related art, both ends of a film member having an opening are attached to film winding shafts rotatably mounted in an air conditioning case. Further, the film member is moved in an air passage of the air conditioning case by the film winding shafts. However, in this case, the film member slides on the air conditioning case around an opening portion of the air passage. Therefore, friction force, generated between the film member and the air conditioning case, is necessarily applied to the film member. Furthermore, because the film member is pushed to the opening portion by pressure of the blown air, the friction force of the film member due to the sliding of the film member is further increased. As a result, a special material, which has low friction, and large tensile strength and large tear strength against the friction force, is required to be used as the film member, thereby increasing production cost of the film member. Further, because drive force for moving the film member is increased due to the sliding friction force of the film member, a high torque actuator is required for driving the film member, thereby further increasing production cost of the air passage opening/closing device.